Inelastic transitions and counterflow tunneling in double-dot quantum ratchets

Date
2010
Advisor
Instructor
Source Title
Physical Review B - Condensed Matter and Materials Physics
Print ISSN
1098-0121
Electronic ISSN
Publisher
The American Physical Society
Volume
82
Issue
20
Pages
205312-1 - 205312-7
Language
English
Type
Article
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Abstract

The ratchet regime of unbiased double quantum dots driven out of equilibrium by an independently biased nearby detector has been theoretically studied using the nonequilibrium Keldysh formalism and the random-phase approximation for the Coulomb effects. When the detector is suitably biased the energy exchange between the two systems removes the Coulomb blockade on the double dot via inelastic interdot tunneling. The energy detuning determines whether the current flows in the same direction as the driving current (positive flow) or in the opposite direction (electronic counterflow). In both cases the intradot transitions lead to negative-differential conductance. Besides the ratchet contribution to the current we also single out a Coulomb drag component.

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Published Version (Please cite this version)